Kraken are sometimes a target of reverse genocide, as they are worth a high amount of experience points (even more than the Riders and below only that of some of the demon princes) and only have one hit point outside of water.

Out from the water a long sinuous tentacle
had crawled; it was pale-green and luminous
and wet. Its fingered end had a hold of Frodo's
foot, and was dragging him into the water.
Sam on his knees was now slashing at it with
a knife. The arm let go of Frodo, and Sam
pulled him away, crying out for help.
Twenty other arms came rippling out. The
dark water boiled, and there was a hideous stench.